There are many applications, particularly in the automotive industry, which call for the use of engineered welded blanks (EWB), also referred to as tailor welded blanks (TWB). These types of blanks can reduce the cost, weight and complexity of certain parts without sacrificing structural integrity. For instance, a common application is in automotive door panels, where the EWB or TWB is generally comprised of a thin piece of sheet metal butt welded to a thicker piece of sheet metal to form a unitary blank. For the majority of the door panel area, the thinner sheet metal will suffice; however, for areas such as mounting points for the door hinges, thicker, stronger sheet metal is required. Thus, the EWB or TWB exhibits increased strength along those areas where it is needed without having to construct the entire door panel out of the heavier, more costly, thicker sheet metal.
Laser welding, which can be used as an alternative to more conventional techniques such as mash seam welding, is a well known EWB or TWB welding technique that is capable of producing a high quality, precision welded blank. Thus, a laser welded blank can be a type of engineered welded blank. According to one laser welding method, two blanks, one being thicker than the other, are brought into contact with one another such that their straight edges are in abutment. Once they are abutted, upper and lower clamping components are brought into contact with the sheet metal pieces such that they firmly retain them in place. A high powered laser beam is then directed along the interface of the abutted edges, usually at a slight angle, such that a uniform linear weld is created. Some applications, referred to as static installations, maintain the pieces of sheet metal in a stationary position while the laser welding unit moves along the interface. Conversely, other applications keep the laser welding unit stationary while indexing the two pieces of sheet metal. Techniques such as these are already known in the art, and are taught in references such as U.S. Pat. No. 5,614,112 issued Mar. 25, 1997 to Peru et al. and U.S. Pat. No. 5,328,083 issued Jul. 12, 1994 also to Peru et al.
The prior art products and techniques discussed above are sufficient for certain applications; however, there is still much room for improvement. It is a general object of the present invention to provide an engineered welded blank and a method for producing the same that includes an improved weld seam.